To make it super simple BRDF is the equation that you have in your vertex/pixel shader for calculating a color.
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The method of rendering and a BRDF selection are two separate topics. Like if I used phong glsl type of shading does that automatically use the bdrf rendering?
#Application development with qt creator 2nd edition how to
For starters I suggest to try and do a single closest light shadowmap and render whole scene to it so you can learn how to do it. Render only the most important objects into the shadowmaps and don't include those that contribute little to the whole image.īut these are optimizations for later. something moved into or out of the light cone) and only re-render that shadowmap then. Detect if anything in the light cone changed (i.e. render shadows only for a couple of the closest lights. First of all limit the maximum number of dynamic light sources i.e. Games usually do multiple different optimizations to make the shadowmaps rendering less costly. If you want the lights to move or have moving objects in the scene you'll need to re-render shadowmaps more often. If your scene is static and your lights don't move you can render them once at the start and reuse. Some types of games can get away with smaller ones, but you have to experiment what looks good for you.Īs for when are the shadowmaps rendered - it depends. Games usually use shadowmaps somewhere in the range 512x512 to 2048x2048 (remember that power of two sized textures are much faster on the GPU). The bigger the texture the less jaggy the shadows will be but also it's gonna be slower because there's more depth information to write. If it's larger it's in the shadow.įor the shadowmap you use a square depth texture and as for the size of it games usually have shadow quality preset for that e.g. If it's smaller then pixel is in the direct light. Then, in the second pass, you bind these shadowmaps as input and when you draw your scene to the actual framebuffer you reproject the 3d position of the pixel you're currently drawing to the light space coordinates and compare the resulting depth value with that in the shadowmap. This basically "encodes" the distance of each object to each light in the depth buffer. You don't need a color buffer in that pass, only the depth information is what's of interest here. Each light gets its own depth buffer like that. you render the scene from the position and direction of your spotlight, so that it's a circle that fills the framebuffer. In the shadow-mapping technique described there you render the scene multiple times.įor each light you set up a model-view-projection matrix to match the light source point of view i.e. Also there's no raytracing involved in the shadow technique described in the previous link.
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That last one -bloom is a postprocess effect and it has nothing to do with shadows.